Decorative lighting, such as holiday lighting includes strings of bulbs spaced out along a pair of wires. The bulbs may be incandescent or now more frequently, LEDs. Light strings can be made much more interesting if they can switch illumination state, color, or other special effects. Twinkling is particularly attractive. Twinkling or flashing as the bulbs change from on to off, at different frequencies or different illumination slopes to give the visual impression that the bulbs are shimmering.
To create these special effects, the bulbs can be directly wired to a power source which controls the current flow in such a way as to pulse/twinkle or create other special lighting effects. To control bulbs in such a manner, would either require multiple conductors to each bulb for individual control or multiple conductors creating different circuits to alternatingly spaced bulbs to create simulate random sequencing of changing color, shimmering, or flashing.
Alternatively, the bulbs may contain their own microcontroller built into each or some of the bulbs or lamp holders, such that normal wiring can be used, however, the disadvantage to this construction is that the user is not able to select the mode of those lights, such as all being steady illuminating in one mode, and another mode where they perform their intended function of the microcontroller electrically connected to those individual bulbs.
In an alternative construction, bulbs may include addressable circuits which allow digital control signals to be sent to all bulbs in a wired string, and the signal intended by a particular bulb can be decoded by IP or other addressing, to control only that bulb. Such an addressable solution is expensive because it requires advanced logic be provided at the power source and each bulb must have a decoder.
Therefore, to obtain the benefits of control of function and illumination method of bulbs without additional wiring, sophisticated, or expensive circuits has not been possible.
It has been shown in the market that people would like the option to have single light set that can offer both a steady on lighting effect and other lighting effects, such as a twinkling effect that can be user selected, so that depending on the mood of the user, or event, the lights can either be set to be steady on or twinkle, color changing, or other switchable effects.
Twinkling can be described as a change in brightness (ramping up/down, dimming) or a switching on/off and changing the frequency of the switching or both including the separate control of red, green and blue LEDs in a single lamp structure to create color changing effects that include fading or flashing.